The present invention relates to an ambient stable beverage, particularly a tea based beverage, that is preserved by a minimal amount of sorbic or benzoic acid.
In recent years there has been an ever increasing choice for consumers who wish to quench their thirst with ready made beverages. Many of those are now turning from the well known soft drinks to tea based beverages, be those carbonated or still, and the xe2x80x9cnaturalxe2x80x9d refreshment they can provide.
Tea contains a complex combination of enzymes, biochemical intermediates and structural elements normally associated with plant growth and photosynthesis. There are also many natural substances that give tea its unique taste, astringency, aroma and colour. Many of these are produced by the oxidation reactions that occur during the so-called fermentation stage of black tea manufacture. Tea production has long been driven by traditional processing methods with only a fundamental understanding of the chemistry that is involved. As a consequence manufacturers have discovered making ambient stable tea based beverages at the volumes required to compete with more traditional soft drinks is not simply a matter of flavouring a soft drink with tea.
The flavour of a tea based beverage and its stability rely on the stability of the beverage as a whole. The fungi including yeasts and moulds that can grow in tea based beverages and other soft drinks can be killed by heat treatment or at least controlled by use of preservatives. Some tea based beverages are therefore pasteurised and then bottled in glass or special heat stable PET containers. This is known as xe2x80x9chot fillingxe2x80x9d. Unfortunately this can be an expensive operation that creates a great deal of environmentally unfriendly waste. It has therefore become more attractive for manufacturers to pack their tea based products in standard PET containers which can range from single serve units to multi-serve packs and maintain the stability of the product using tailor made flavour and preservative systems. This is known as xe2x80x9ccold fillingxe2x80x9d. It is also useful in that one can readily use a tea concentrate or powder.
Potassium sorbate is well known preservative. It is a mould and yeast inhibitor and one of the few legally permitted preservatives of soft drinks and fruit juices. It has been listed in the UK Preservatives in Food regulations since at least 1962. The levels of use tend to be in the range of 100-1000 ppm. That has been found to be an effective antimicrobial agent in a variety of foods including carbonated beverages in certain fruit and vegetable products, including wines. It is sorbic acid that is the effective agent.
Unfortunately even moderate levels of sorbic or benzoic acid can seriously affect the flavour of a tea based beverage. Adding a strong flavour such as lemon can offset the preservative taste. However consumers are keen to experience other flavours, often more delicate flavours. Furthermore, some of those consumers that were drawn to tea based products as a more healthy and natural alternative to soft drinks would reduce their intake of preservatives generally.
The applicants addressed a similar problem with resect to tea based beverages in U.S. Pat. No. 6,036,986. However the solution proposed there was to gradually adjust water hardness and pH and gradually add polyphosphate, benzoic acid, sorbic acid and cinnamic acid.
However there is still a need for pleasantly flavoured, ambient-stable, tea based beverages that contain minimal amounts of preservatives such as sorbic and benzoic acids. Non-tea based beverages including fruit and soft drinks can be stabilised in a similar way.
In response to that need the present inventors have now developed an ambient stable beverage that is preserved by a minimal amount of sorbic or benzoic acid.
The invention can in broad terms be said to relate to an ambient stable beverage, particularly a tea based beverage, that contains a preservative system comprising 1 to 175 ppm cinnamic acid, 10 to 200 ppm sorbic acid or benzoic acid, and at least one essential oil other than cinnamic acid. When the beverage is tea based it preferably contains 0.01 to 3% tea solids, especially about 0.14% tea solids.
The beverage preferably contains 1 to 100 ppm of the essential oil.
The invention can also be said to relate to a method for preparing an ambient-stable tea based beverage suitable for cold filing comprising preserving a tea extract with a preservative system comprising 1 to 175 ppm cinnamic acid, 10 to 200 ppm sorbic acid or benzoic acid, and at least one essential oil other than cinnamic acid.
xe2x80x9cBeveragexe2x80x9d for the purposes of the present invention means any drink, other than water, and includes soft drinks, fruit drinks, coffee based drinks and tea based drinks.
xe2x80x9cEssential oilxe2x80x9d for the purposes of the present invention includes any of the volatile oils in plants having the odour or flavour of the plant from which they are extracted. It also includes one or more of the components of that oil that is or are responsible for or at least contributes to the odour or flavour of that plant.
xe2x80x9cTeaxe2x80x9d for the purposes of the present invention means leaf material from Camellia sinensis var. sinensis or Camellia sinensis var. assamica. xe2x80x9cTeaxe2x80x9d is also intended to include the product of blending two or more of any of these teas.
For the avoidance of doubt the word xe2x80x9ccomprisingxe2x80x9d is intended to mean including but not necessarily xe2x80x9cconsisting ofxe2x80x9d or xe2x80x9ccomposed ofxe2x80x9d. In other words the listed steps or options need not be exhaustive.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or concentrations of material ought to be understood as modified by the word xe2x80x9caboutxe2x80x9d.